The present exemplary embodiment relates generally to an electrophotographic printing system. It finds particular application in conjunction with a sheet feeder control system and method for improving the feeding of copy sheets that accompanies this general process of copying and printing, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
In the process of electrophotographic reproduction, a light image of an original to be copied or printed is typically recorded in the form of a latent electrostatic image upon a photosensitive member, with a subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The visual toner image can be either fixed directly upon the photosensitive member or transferred from the member to another support medium or substrate, such as a sheet of plain paper. To render this toner image permanent, the image must be “fixed” or “fused” to the paper, generally by the application of heat and pressure.
With the advent of high speed xerography reproduction machines wherein copiers or printers can produced at a rate in excess of three thousand copies per hour, the sheet handling system must feed paper or other media through each process station in a rapid succession in a reliable and dependable manner in order to utilize the full capabilities of the reproduction machine. The sheet handling systems must operate flawlessly to virtually eliminate risk of damaging the recording sheets and generate minimum machine shutdowns due to misfeeds or multifeeds.
A high speed xerography reproduction machine typically includes a feeder assembly for feeding substrates to the image transfer portion of the machine. The feeder assembly may employ vacuum corrugated feeder technology, friction retard feeder technology, or shuttle feeder technology. The feeder typically has a fixed set of operating parameters. These settings may be the best compromise for feeding most types of substrates, and, as a result, the substrate feeding capability is generally limited to the range that these parameters allow. While this approach may satisfy the needs of general use copying/printing, it limits the range of substrates that can be fed in the production environment where expanded range is needed. Further, many of the users or operators in the production environment typically come from the offset lithography environment, and they are accustomed to “tuning” their machines for the substrates they are running. Offset lithography is the workhorse of printing. Almost every commercial printer employs it. And the quality of the final product is often due to the guidance, expertise and equipment provided by the printer.
Thus, there is a need for a feeder control system and method which provides the users of high speed xerographic machines the ability to adjust some of the feeder operating parameters to expand the range of substrates (from very light to heavy weight) that can be used with the machines.